I adore SJs as family, friends, and coworkers, but in a romantic relationship, I'm skeptical that it could work. I've been in probably five or six serious or semi-serious relationships and not a single one was SJ because the attraction was just not there for me. (I've been attracted to pretty much exclusively SPs and NPs.)
I don't want to sound harsh against SJs because I really do value their gifts. I'm an elementary school teacher and I absolutely love my little SJ students, particularly the ISFJs and ISTJs who are such sincere, responsible little worker bees.
And I don't want to make it sound like hard work is all there is to SJs because they do have a deeper, quirkier side to their personalities, but because of temperament that side of them comes in second to their work ethic and sense of responsibility. A lot of ISXJs have a fun, extraverted-sensing side that comes out once in a while to play. (Example: my conservative, traditional ISXJ parents announced out of the blue at my little sister's high school graduation that they were planning a trip to Las Vegas.) It just doesn't come out too often (they work first and only play if there's time).
Once after I was burned in a relationship, I actually made it a goal to date someone more like my ISTJ father, because he has always been caring, responsible, and devoted to my mother. I found myself a nice gentlemanly ISTJ and we started casually dating. He was ready to get more serious.... but I just couldn't do it! I felt bad but I had to break it off. Maybe an extraverted NF would have had better luck, but for me, I tend toward being too serious and regimented as it is, so I really need a partner who can help me access my fun, goofy side.